1. Field of the Invention
The present invention relates to a copying machine in which a document is transported to an exposure device to obtain a copy image, and more particularly to a copying machine capable of detecting the trouble of a transporting motor in a document transport stopping mode.
2. Description of the Prior Arts
Conventionally, copying machines have been proposed wherein a document is transported to a fixed exposure device to effect exposure and scanning. An example of these copying machines is constructed such that a document is supported and transported by a transporting roller to effect rapid exposure and scanning.
In the above-mentioned copying machines wherein a document is transported to a fixed exposure device, the document should not be damaged during its transportation. However, the document may be damaged by being transported due to the abnormal operation of the motor for driving the transport roller in a stop mode in which the document should not be transported.
In view of this, a machine has been proposed which is provided with a pulse encoder generating the pulse corresponding to the rotation of the transport roller. In such a machine, troubles which occur during the transportation of the document may be detected by detecting, from the output of the pulse, the presence of the document.
However, when paper jamming occurs, the document transport portion is required to be exposed to remove the jamming document. In this case, the document may wind around the transport roller, with the result that said transport roller is caused to rotate upon the removal of the jamming document.
Therefore, the rotation of the transport roller for the removal of the document cannot be discriminated from that of the roller caused by the abnormal operation of the motor.